One Way Drive?

(An iPod Ad in NYC)

It was in 1980s. I usually went to the local markets with my grandpa. When we bought or sold things, I noticed that grandpa could count the numbers very quickly though he did not learn higher education. Even he was not counting those numbers on paper, but in his mind and memory. Amazing!

My dad, a middle class educator who was a secretary of the village-track of four villages, often used pen and papers to count the numbers.

Me? I used to count the numbers in my mind and by calculator, as well.

When I got in Thailand, I bought a book from a store. Price of the book was 12 bahts. I gave a banknote of 20 bahts to the seller. I noticed that the seller was using calculator to count the change between 20 bahts and 12 bahts.

Now, I am in the United States where we don’t need to know what makes five minus two, since computers, credit companies and banks do the job.
As the above picture, which I took in the New York City, are we going on a one way drive?